低mAs-CT低分辨率水模图像质量的实验研究

Experimental Study of Effect of Low Tube Current-Time Product Technique on Image Quality at CT with Low-contrast detection modulus Phantom

目的:探讨CT检查中低管电流-时间乘积技术低分辨率水模图像质量。方法:设置多种管电流-时间乘积,5和10mm层厚,多种重建算法,对Catphan500模型进行CT扫描,记录CT值,SD值,并计算CNR值。同时运用统计学方法和Excel表格对获得的数据进行统计分析。结果:管电流-时间乘积、射线剂量、层厚和图像质量成正比关系,不同的重建算法对图像质量会产生不同的影响。结论:低管电流-时间乘积能够降低射线剂量,但是剂量减少会增加图像噪声,影响图像质量,增加层厚和使用soft重建算法可以达到降低图像噪声的目的。

Objective：To investigate the effect of low tube current-time product technique on image quality at computed tomography （CT） with Low-contrast detection modulus Phantom. Methods：The parameters milliampere seconds,section thickness and reconstruction algorithm were varied for the scanning with a phantom,Catphan 500. Then the data CT numbers,SD values and the calculated CNR values measured from the images with the phantom were recorded. Statistical analysis was performed by using ANOVA, the two-tailed paired t test,Dunnett-t test,nonparametric test,and EXCEL table. Results： Imag quality was direct proportion to the tube current-time product, radiation dose and section thickness, but reconstruction algorithm effected the image quality was diverse. Conclusion： Reduced tube current-time product decreased the radiation dose,but the image quality was degression simultaneously. By using reconstruction algorithm, soft, and increasing section thickness, the image quality was improved.